Transparency International has released its Global Corruption Barometer for 2004. All 23 pages of it are available as a pdf file here. The group’s work is a little controversial among people who study corruption because they conduct surveys on how much institutions are perceived in public opinion (among 50,000 respondents in 64 countries) as being corrupt rather than studying corruption itself. Perceptions are not completely irrelevant, however, considering that trust in institutions in an important variable in measuring how stable they are likely to be and how likely they are to be perceived as legitimate.
The five institutions perceived as being most corrupt are: 1) political parties, 2) legislatures and parliaments, 3) police, 4) the judiciary, and 5) tax revenue agencies. There is some variation, though: in the US, Canada and some European countries, media outlets make people's top three. 45% of respondents globally expect levels of corruption to increase in the coming three years (up from 42% in 2003), while 17% expect a decrease (down from 20% in 2003).
Obviously it is hard to draw very many meaningful conclusions from a sample as diverse as this, encompassing 64 countries with a wide range of conditions and situations. They do give aggregate data on individual countries in Appendix IV, but not in enough detail to do the kind of cross-tabulation they do in the text of the report. It’s interesting data-gathering, and it cries out for some independent analysis that would produce some good theory.